1. Field of the Invention
The present invention relates to a cassette loading apparatus utilizable in a magnetic recording/reproducing apparatus such as a video tape recorder and the other kinds of data processing apparatuses, etc.
2. Description of the Prior Art
Recent tape cassettes and video tape recorders of the latest model as well have become compact in size subsequent to a tendency to magnetic recording with high density. As a result, usage of the video tape recorders (hereinafter referred to as VTR) has been expanded to outdoors to pick up the scenery or the like although it was conventionally centered mainly on indoor use, e.g., for recording a television program or reproducing a software.
As such, in consideration into the outdoor use of the VTR and as a dust-proof means, a new kind of a tape cassette has been put into practical application that is equipped with two lids so as to cover the front and rear faces of the tape.
Moreover, a new model of a cassette loading apparatus fit for the VTR accommodating the above-described tape cassette of two lids has been proposed and brought into commercial market.
The above expansion of the usage of the VTR has also increased occasions to record data by means of a camcorder with a small-size tape cassette and to edit the same by an editing VTR with a large-size tape cassette.
In such case as above, it becomes necessary to load a plurality of tape cassettes of different size in the same VTR, and some cassette loading apparatuses already in use can achieve the purpose.
Hereinbelow, the conventional tape cassette loading apparatus of the type referred to above will be described with reference to the accompanying drawings.
In the first place, the structure of lids of a tape cassette loaded in the cassette loading apparatus will be explained.
Referring to FIG. 1, a tape cassette 1 is comprised of an upper half 2 and a lower half 3. The tape cassette 1 has an opening 4 at the front face thereof. A tape 5 is loaded in the opening 4 in the stretching state. The opening 4 is normally covered with a front lid 6 and a rear lid 7.
The front lid 6 is, as shown in FIG. 2, generally in U-shape and supported at a pair of fulcrum pins 9,9' at the left and right lateral faces thereof 8. The fulcrum pins 9,9' are inserted into a pair of notched parts 10 formed at the left and right ends of the upper half 2. Therefore, the front lid 6 is rotatable around the fulcrum pins 9,9'. Since there is provided a coil spring 11 at the side of the fulcrum pin 9', the front lid 6 is normally urged in a direction to close the lid.
There are a pair of bracket parts 13,13 at the lower f ace of an upper part 12 of the front lid 6. A pair of supporting pins 15,15 provided at the opposite lateral ends of the rear lid 7 are inserted into pin holes 14 of the respective bracket parts 13,13, so that the rear lid 7 is rotatable around the pair of the supporting pins 15.
A pair of rear lid guide grooves 17 are formed behind a pair of tape guides 16 of the lower half 3. A pair of guide pins 19 in a pair of bracket parts 18 at the lateral ends of the rear lid 7 are inserted slidably into the rear lid guide grooves 17. The front lid 6 and rear lid 7 of the tape cassette 1 are coupled to each other in the above-described fashion. Therefore, if either of the lids 6 and 7 is let opened, both the front and rear lids 6 and 7 are opened simultaneously.
Next, an example of the conventional cassette loading apparatus will be depicted with reference to the drawings.
FIGS. 3 and 4 are respectively an exploded perspective view and a perspective view of a conventional cassette loading apparatus. A cassette holder 20 of the apparatus moves the cassette 1 to a predetermined position within the VTR. Guide pins 21 are formed in the cassette holder 20 and guide angles 22 fixed to the cassette holder 20. Side plates 23 are secured to a chassis 24 in the VTR. Moreover, each side plate 23 has guide grooves 23a which are meshed with the guide pins 21. A top plate 25 is rigidly secured to the side plates 23. A rear lid opener 26 is fixed to the chassis 24 through a mounting plate 27.
The cassette loading apparatus in the above-described structure operates as follows.
When the tape cassette 1 is inserted into the cassette holder 20, the cassette holder 20 moves along the guide grooves 23a formed in the side plates 23 (the driving unit thereof is not shown). The cassette 1 is thus loaded at a predetermined position within the VTR.
During this movement of the cassette holder 20 in a vertical direction, as shown in FIGS. 5 and 6, a lower end face 7a of the rear lid 7 is brought to butt against the rear lid opener 26 of the loading apparatus. As the tape cassette 1 is further moved downwards, the lower end face 7a of the rear lid 7 is thrusted to the rear lid opener 26 and guided along the guide grooves 17, so that the rear lid 7 is opened. At the same time, the front lid 6 which has the rear lid 7 mounted in a rotatable manner is turned in an opening direction against the coil spring 11.
The lids of the conventional tape cassette loading apparatus are opened in the manner as described hereinabove. On the other hand, they are closed in the order of the operation opposite to the above.
In the case where the lids of a tape cassette are opened/closed in the above-depicted manner as in the conventional cassette loading apparatus, it becomes possible to open/close lids of the tape cassettes 28, 29 of different size shown in FIG. 8.
In general, when tape cassettes of different size and of the same system are loaded in the same apparatus, an opening portion 30 (indicated by oblique lines) at the front faces of the tape cassettes 28,29 is used in common, while the reels 31,32 and tape cassettes 28,29 are different in size. Each lid of the cassettes is formed in the same structure as described with reference to FIGS. 1 and 2.
Since the opening portion 30 is common for the tape cassettes 28,29, a rear lid 33 can be made common for both tape cassettes, as indicated in FIG. 8.
If the lids are opened/closed as in the foregoing conventional manner, a plurality of kinds of tape cassettes can be opened/closed by the single rear lid opener.
However, the rear lid opener 26 is brought to butt into contact with the lower end face 7a of the rear lid 7 in the prior art, as shown in FIG. 9, which causes a disadvantageous approach of the rear lid opener 26 to the tape 5 stretched in the opening 4 as the lid is being opened. Therefore, if the tape 5 gets slightly loose at this time, the rear lid opener 26 touches the tape 5, resulting in a damage or break of the tape.
Besides, since the lower end face 7a at the central part in an elongated direction thereof (part A in FIG. 1) is held in thrusting contact with the rear lid opener 26 so as to keep the lids opened, the central part A of the rear lid 7 is greatly deflected so much as to be deformed with time. Therefore, the height of the rear lid 7 in the elongated direction when it is opened is variously changed. Moreover, the above-mentioned deflection proceeds to an eternal deformation of the lid, generating a gap at a part 34 (FIG. 5) where the front lid 6 meets the lower end face 7a of the rear lid 7 in the closing state. As a result, it disadvantageously takes place that dusts or the like evading through the gap are adhered to the tape 5, and an undesirable increase of drop-outs is noticed.
Furthermore, in the case where the front and rear lids of the tape cassettes 1,29 having large front lids 6,35 as shown in FIG. 1 or 8 are to be opened/closed, a considerable amount of load is required therefor. However, since the front and rear lids are opened/closed by the rear lid opener 26 alone in the prior art, the rear lid opener 26 cannot get rid of a great deal of load, whereby it may be broken or the rear lid of the tape cassette may be broken in some cases.